8th Ed. Character Assassination Help - Let us count the ways

A common theme with a lot of games I am playing is that the characters I play against seem to be the cornerstone of every army I face, whether it be a BSB, the general or a wizard. Especially when I am facing Skaven, that leadership has to go!

I have only been playing fantasy for around 6-8 months or so, so I am still fairly in-experienced and I see terms like "hero hunter" or "assassination build" thrown around quite a lot with no real explanation of how to do build it or how to use it. I am very very interested in finding the best ways to assassinate characters (especially characters in a unit).

I know there are 3 death spells and 1 high magic spell that are good for this, but other than that, I'm not sure what else can be done. Skink chief on a Ripperdactyl? scarvet on a coldone? he isn't really expendable though.

This strategy is difficult to pull off because your opponent can simply challenge your lone character with a unit champ and you are forced to accept. Then you likely lose combat due to static combat resolution.

A unit of Ripperdactyls can work given the right conditions. First the character has to be pretty squishy. Second you have to mark the unit with the blot toad. Lastly, the Rippers have to have higher initiative than the unit, otherwise they get obliterated before they get to strike.

Depending on the Strength of the character in question, Dwellers Below can be used to take the character out (and a good chunk of his unit).

Without the lore of Death, we don't have a lot of options to assassinate enemy characters, I normally try to break the character's unit and destroy the character when it flees. If you are taking High Magic Arcane Unforging can hopefully knock out whatever magical item is keeping them alive in close combat.

I guess I'm not a huge fan of Ripperdactyls (I hate compulsory charges) so I never tried using them as a grenade to knock out enemy characters.